Can you show up at WalMart with a photo of a broken television and get a refund? Can you go to Lowes and tell them the dish washer you bought was defective so you tossed it out, they need to give you a refund? No. Virtually nobody does business that way. You can bow down and discount it if you want to, it's your money. You can play nice if you want to, be the doormat. Or you can act like any professional business and tell them to return the signs so you can investigate the issue or they can pay the full amount. You don't have to play the asshole game, you don't have to get upset, but you damn sure don't have to be the victim either. Why are you even discussing this here instead of with them?